when to re-apply more anit-foul

tudorsailor

tudorsailor

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I bought my yacht 6 years ago when it was 5 years old. In the past 5 years till last year I had 2 coats of anti-foul applied. As a result, this year there was so much anti-foul that it was not holding onto the hull and flaked off in big areas. I have now had all the antifoul removed back down to the gelcoat, then sealed, primed and finally repainted with International Micron anti-foul.

The yacht lives in the Western Med. It is sailed for 14 weeks a year

My question is how can I judge further anti-foul application. It seems that 2 coats a year is too much. Since the anti-foul is meant to come away with time, do I wait until I can see the primer before re-applying? Do I get one coat a year rather than two?

Sorry for a naive question

Thanks

TudorSailor
 
It's not a naive question. Most people seem to find that fouling varies from year to year and you can only make a general rule for your area of cruising and mooring. Why not experiment and try one coat, or ask around what other boats are using successfully? A soft eroding A/F will build up over time, but you should get quite a few years before you have to have the hull cleaned and start again.
 
Here in Largs one "thinned" coat of International Cruising Uno antifouling is more than enough for 8/9 months in the water. Two coats are a complete overkill except on trailing edges and the waterline. I know from painful flaking experience on previous boats after 5/7 years, also the effort and cost required to do two!

Sometimes I wonder whether I should do any more than the trailing edges / waterline. The boat normally comes out so clean, but think I need to do just to get an "active" surface for the new season.
 
One coat all over; 2 on leading/trailing edges and the first 2-3 feet of the bow and the waterline.

Used to use 1 tin (2.5L) of Optima on 38.5ft fin keeler - about half of the recommended amount - worked well enough for me.

On liftout and after a pressure wash I expect to see areas through to the primer.
 
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I think it's a great question and one to which most of us can relate in one way or another.

My boat is now 10 years old. It, too, had been suffering from large areas of flaking. About 3 seasons ago, I simply scrapped the flakes back to adhesion (no small job in itself) and antifouled those bare areas only. I use Cruiser Uno. It seems to be just as effective as a full coat.

I've never applied 2 coats to any of the boats I've owned. The max has only ever been 1 full coat plus leading edges of the keel and rudder.

I wish their was a magic wand solution to removing AF. I'm thinking about trying an area with caustic soda held in place with wall paper paste this coming season. Anyone done this successfully? How much caustic soda to water?

For me, it's the worst job required in support of boat ownership. Whenever I'm applying AF I wear two pairs of gloves but know that 2 weeks later I'll shed a layer of skin from my hands.
 
Glad I am not alone in this dilemma.

Now that I will have a lovely new layer of anti-foul, I think that I wait to see primer peaking through after being sprayed off before re-applying?

Tudorsailor
 
Just as a follow-up...

I have just received some advice from a yacht maintenance professional. He says that at the annual haul out one should scrub off the existing anti-foul with 3M doodlebug scotchpad while the hull is wet. Only then should a new coat of anti-foul be applied.

I guess that will ensure no build up

Does anyone do this in practise?

Thanks

TudorSailor
 
tudorsailor said:
Just as a follow-up...

I have just received some advice from a yacht maintenance professional. He says that at the annual haul out one should scrub off the existing anti-foul with 3M doodlebug scotchpad while the hull is wet. Only then should a new coat of anti-foul be applied.

I guess that will ensure no build up

Does anyone do this in practise?

Thanks

TudorSailor
Click to expand...

I do. It's a bit of extra work, but it's a lot easier than longboarding which I regularly get roped in to on the racer. The secret is keeping the areas you are working on wet.

I use scourers (B&Q or otherwise - the ones that say not to be used on non-stick pans because they're too rough).
 
Usually one would apply fresh antifoul (2 coats leading and trailing edges ans 1-2 feet from the waterline down) get a bit of fouling, pressure wash off and re apply new fouling of the same kind and repeat annually. The problem comes when the previous years doesn't work and you swap antifoul. The different antifouls don't adhere to each other, and next year you're left with flakey antifoul.

So......Either thoroughly remove any previous antifoul before applying the new stuff, or apply the correct primer, but this will only adhere to the old paint, so if that's duff the new stuff will flake off.
 
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